Ok I know this is kinda redundant based on my earlier post. I'm changing the terminology and focus.

I'll give you an air mobile launch platform capable of delivering your rocket with a max weight of 40 tons (80,000 lbs) and max dimensions of 40 X 10 X 20 feet to an alt. of 20 miles with a vertical speed of 1,500 mph. from any airport where it is allowed and the runway is long enough (I.E. if a 747 takes off from there were probably ok) I realize costal airports will be favored or it's own airport would be built. Your launch destination is up to you (somewhere over the Atlantic, Pacific, ...ect)

What could you do under those specifications? What your your rocket look like and do?

The second stage and payload of whatever you prefer. Either a traditional cylindrical rocket or a winged thing if you're sporty. Your air launch thingy is just a first stage booster. The advantages it has is I presume full re-usability and that you don't need a rocket range and its attendant perceived risk red-tape/cost.

What about a very large blimp that is shaped like an umbrella with a hole in the center, witg two very strong cables hanging down, the ship uses the drag of the massive umbrella shape to counter its acceleration as it launches itself using current from the cables to pull on the umbrella as a reaction mass or tue umbrella could drop something much heavier attached to the other end of the cable, launching through the eye of the umbrella.....

_________________Let not the bindings of society hold you back from improving it.... the masses follow where the bold explore.

It would have to and extraordinarily ridiculously large airship in order to lift any kind of significant "payload" (which is actually the payload + to-orbit stage). Probably more expensive and less reliable than current means. A hundred thousand cubic feet of Helium isn't cheap.

Build it in stages at high altitude, use hydrogen.... the higher up the less O2 to go boom!Cover top in solar and use electrolosis of condensate to make fuel as well as atmo..... lift ships to deployer via a smaller blimp with no fuel in it so its lite.

The nice thing here is that solar works well above the clouds...

_________________Let not the bindings of society hold you back from improving it.... the masses follow where the bold explore.